Cmos image sensor structure with crosstalk improvement

ABSTRACT

A semiconductor device includes a substrate, a device layer, color filters and a passivation layer. The device overlies the substrate, and has a first surface and a second surface opposite to the first surface. The device layer includes a grid structure disposed on the second surface of the device layer, and the grid structure includes cavities. The first surface of the device layer is adjacent to the substrate. The color filters fill in the cavities. The passivation layer is disposed on the second surface of the device layer, and covers the grid structure and the color filters.

BACKGROUND

Semiconductor image sensors are operated to sense light. Typically, thesemiconductor image sensors include complementarymetal-oxide-semiconductor (CMOS) image sensors (CIS) and charge-coupleddevice (CCD) sensors, which are widely used in various applications suchas digital still camera (DSC), mobile phone camera, digital video (DV)and digital video recorder (DVR) applications. These semiconductor imagesensors utilize an array of image sensor elements, each image sensorelement including a photodiode and other elements, to absorb light andconvert the sensed light into digital data or electrical signals.

Front side illuminated (FSI) CMOS image sensors and back sideilluminated (BSI) CMOS image sensors are two types of CMOS imagesensors. The FSI CMOS image sensors are operable to detect lightprojected from their front side while the BSI CMOS image sensors areoperable to detect light projected from their backside. The BSI CMOSimage sensors can shorten optical paths and increase fill factors toimprove light sensitivity per unit area and quantum efficiency, and canreduce cross talk and photo response non-uniformity. Hence, the imagequality of the CMOS image sensors can be significantly improved.Furthermore, the BSI CMOS image sensors have high chief ray angles,which allow shorter lens heights to be implemented, so that thinnercamera modules are achieved. Accordingly, the BSI CMOS image sensortechnology is becoming a mainstream technology.

However, while existing BSI CMOS image sensors have been generallyadequate for their intended purposes, they have not been entirelysatisfactory in every aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic cross-sectional view of a semiconductor device inaccordance with various embodiments.

FIG. 2A through FIG. 2H are schematic cross-sectional views ofintermediate stages showing a method for manufacturing a semiconductordevice in accordance with various embodiments.

FIG. 3 is a flow chart of a method for manufacturing a semiconductordevice in accordance with various embodiments.

FIG. 4 is a flow chart of a method for manufacturing a semiconductordevice in accordance with various embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact.

Terms used herein are only used to describe the specific embodiments,which are not used to limit the claims appended herewith. For example,unless limited otherwise, the term “one” or “the” of the single form mayalso represent the plural form. The terms such as “first” and “second”are used for describing various devices, areas and layers, etc., thoughsuch terms are only used for distinguishing one device, one area or onelayer from another device, another area or another layer. Therefore, thefirst area can also be referred to as the second area without departingfrom the spirit of the claimed subject matter, and the others arededuced by analogy. In addition, the present disclosure may repeatreference numerals and/or letters in the various examples. Thisrepetition is for the purpose of simplicity and clarity and does not initself dictate a relationship between the various embodiments and/orconfigurations discussed. As used herein, the term “and/or” includes anyand all combinations of one or more of the associated listed items.

In a typical BSI CMOS image sensor, a metal grid or an oxide grid isdisposed over a device layer to improve a crosstalk effect of the BSICMOS image sensor. However, in the BSI CMOS image sensor including themetal grid, the metal grid covering the device layer blocks lightprojected from the backside of the BSI CMOS image sensor though themetal grid to the device layer, thus decreasing light absorption of thedevice layer. Accordingly, photoelectrons generated in the device layerare decreased, thereby reducing a quantum efficiency of the BSI CMOSimage sensor. In the BSI CMOS image sensor including the oxide grid, theoxide grid is disposed over the device layer with several dielectriclayers therebetween. After light projected from the backside of the BSICMOS image sensor passes through the oxide grid, the light has to firstpass through the dielectric layers and then to reach the device layer.The light is diffused to adjoining pixels due to the reflection and/orthe refraction occurring between the oxide grid and the device layer,thus causing a crosstalk effect to be increased and worsening the imagequality of the BSI CMOS image sensor.

Embodiments of the present disclosure are directed to providing asemiconductor device and a method for manufacturing the semiconductordevice, in which various cavities are formed in a surface of a devicelayer to form a grid structure on the surface of the device layer, suchthat light projected from the backside of the semiconductor device tothe device layer is not blocked by the grid structure, therebyincreasing light absorption of the device layer. Furthermore, the gridstructure is formed from a portion of the device layer, therebypreventing the light from being diffused from the grid structure to thedevice layer, thus greatly improving a crosstalk effect and increasingthe image quality of the semiconductor device. Moreover, the gridstructure is formed using a portion of the device layer, so as togenerate photoelectrons in the grid structure for increasing brightness.

FIG. 1 is schematic cross-sectional view of a semiconductor device inaccordance with various embodiments. In some embodiments, asemiconductor device 100 is a CMOS image sensor device, which may beoperated for sensing incident light 102. The semiconductor device 100has a front side 104 and a back side 106. In some examples, thesemiconductor device 100 is a BSI CMOS image sensor device, which isoperated to sense the incident light 102 projected from its back side106.

As shown in FIG. 1, the semiconductor device 100 includes a substrate108, a device layer 110, various color filters 112 a-112 d and apassivation layer 114. The substrate 108 is a semiconductor substrate,and may be composed of a single-crystalline semiconductor material or acompound semiconductor material. For example, the substrate 108 is asilicon substrate. In some examples, germanium or glass may also be usedas a material of the substrate 108.

The device layer 110 is disposed over the substrate 108. In someexamples, the device layer 110 is formed from silicon. For example, thedevice layer 110 is formed from epitaxial silicon. The device layer 110has a first surface 116 and a second surface 118, which are located ontwo opposite sides of the device layer 110. The first surface 116 of thedevice layer 110 is adjacent to the substrate 108. The device layer 110includes a grid structure 120 formed on the second surface 118 of thedevice layer 110. The grid structure 120 includes various cavities 122formed in the device layer 110. In some examples, each cavity 122 has across-section in a shape of rectangle. The cavities 122 may beperiodically arranged. A pitch between the cavities 122, a depth, alength and a width of each cavity 122 are modified according torequirements of the semiconductor device 100.

The color filters 112 a, 112 b, 112 c and 112 d are respectivelydisposed in the cavities 122 of the grid structure 120, in which thecolor filters 112 a, 112 b, 112 c and 112 d correspondingly fill thecavities 122. In some examples, as shown in FIG. 1, the semiconductordevice 100 includes four kinds of color filters, i.e. the color filters112 a, 112 b, 112 c and 112 d. The color filters 112 a, 112 b, 112 c and112 d are arranged in sequence and repeatedly. In some exemplaryexamples, the color filters 112 a, 112 b, 112 c and 112 d includes redcolor filters, blue color filters, green color filters and white colorfilters. The white color filters may be formed from silicon oxide. Invarious examples, the semiconductor device 100 may include three kindsof color filters, such as red color filters, green color filters andblue color filters. In some examples, the semiconductor device 100 mayinclude four kinds of color filters, such as red color filters, greencolor filters, blue color filters and yellow color filters.

Referring to FIG. 1 again, the passivation layer 114 is disposed on thesecond surface 118 of the device layer 110, and covers the gridstructure 120 and the color filters 112 a, 112 b, 112 c and 112 d. Thepassivation layer 114 is suitable for use in protecting the gridstructure 120, the color filters 112 a, 112 b, 112 c and 112 d, and thedevice layer 110 from being damaged. The passivation layer 114 may beformed from silicon oxide, silicon nitride or silicon oxynitride.

In some examples, as shown in FIG. 1, the semiconductor device 100 mayoptionally include a lining layer 124. The lining layer 124 covers thegrid structure 120, and is disposed between the color filters 112 a, 112b, 112 c and 112 d and the device layer 110 and between the passivationlayer 114 and the device layer 110, i.e. the lining layer 124 is firstlyformed to cover the grid structure 120 on the second surface 118 of thedevice layer 110, the color filters 112 a, 112 b, 112 c and 112 d aredisposed in the cavities 122 of the grid structure 120 on the lininglayer 124, and then the passivation layer 114 is formed to cover thelining layer 124 and the color filters 112 a, 112 b, 112 c and 112 d.For example, the lining layer 124 may be formed from silicon oxide.

By forming the grid structure 120 on the second surface 118 of thedevice layer 110, a crosstalk effect can be significantly improved sincethe grid structure 120 is a portion of the device layer 110 and there isno distance between the grid structure 120 and the device layer 110. Inaddition, the grid structure 120 is formed using a portion of the devicelayer 110, such that photoelectrons can be generated in the gridstructure 120, thereby increasing brightness. Furthermore, the gridstructure 120 is formed by using a portion of the device layer 110, andthus no additional film is needed for forming the grid structure 120,and the process cost is reduced. Moreover, the color filters 112 a, 112b, 112 c and 112 d are disposed in the cavities 122 of the gridstructure 122, such that thicknesses of the color filters 112 a, 112 b,112 c and 112 d are substantially the same, thereby enabling lighttransmission through the color filters 112 a, 112 b, 112 c and 112 d tobe uniform.

FIG. 2A through FIG. 2H are schematic cross-sectional views ofintermediate stages showing a method for manufacturing a semiconductordevice in accordance with various embodiments. As shown in FIG. 2A, asubstrate 200 is provided. The substrate 200 is a semiconductorsubstrate, and may be composed of a single-crystalline semiconductormaterial or a compound semiconductor material. In some examples,silicon, germanium or glass may be used as a material of the substrate200.

Referring to FIG. 2A again, a device layer 204 is formed on a surface202 of the substrate 200 by using, for example, a deposition technique,an epitaxial technique or a bonding technique. In some examples, theoperation of forming the device layer 204 includes forming the devicelayer 204 from silicon. In certain examples, the device layer 204 isformed from epitaxial silicon. The device layer 204 has a first surface206 and a second surface 208 opposite to the first surface 206. Theoperation of forming the device layer 204 is performed to form the firstsurface 206 of the device layer 204 being adjacent to the surface 202 ofthe substrate 200.

Referring to FIG. 2E firstly, a grid structure 218 is formed on thesecond surface 208 of the device layer 204. The operation of forming thegrid structure 218 includes forming the grid structure 218 includingvarious cavities 220. In some examples, as shown in FIG. 2C, theoperation of forming the grid structure 218 includes forming a masklayer 212 to cover first portions 214 of the second surface 208 of thedevice layer 204 and to expose second portions 216 of the second surface208 of the device layer 204, and removing portions of the device layer204 from each of the second portions 216 of the second surface 208 ofthe device layer 204, so as to form the cavities 220 in the device layer204. The operation of forming the mask layer 212 may include forming themask layer 212 from silicon oxide.

In some exemplary examples, as shown in FIG. 2B and FIG. 2C, theoperation of forming the mask layer 212 includes forming a mask materiallayer 210 to blanketly cover the second surface 208 of the device layer204, and removing portions of the mask material layer 210 on the secondportions 216 of the second surface 208 of the device layer 204. Forexample, the operation of forming the mask material layer 210 may beperformed using a thermal oxidation process. In the thermal oxidationprocess, the second surface 208 of the device layer 204 is thermallyoxidized to form the mask material layer 210. In addition, the operationof removing the portions of the mask material layer 210 may be performedusing a photolithography technique and an etching technique. After theoperation of removing the portions of the mask material layer 210 iscompleted, the remaining portions of the mask material layer 210 formthe mask layer 212, which are located on the first portions 214 of thesecond surface 208 of the device layer 204, and the second portions 216of the second surface 208 of the device layer 204 are exposed, as shownin FIG. 2C.

In some examples, the operation of removing the portions of the devicelayer 204 from the second portions 216 of the second surface 208 of thedevice layer 204 is performed using an etching technique with the masklayer 212 as an etching mask. For example, the operation of removing theportions of the device layer 204 from the second portions 216 of thesecond surface 208 of the device layer 204 is performed using ananisotropic etch technique. In some exemplary examples, the operation ofremoving the portions of the device layer 204 is performed usingtetramethyl amminium hydroxide (TMAH) as an etchant while the mask layer212 is formed from silicon oxide and the device layer 204 is formed fromsilicon. The TMAH has high etching selectivity between the silicon oxideand silicon, so that the portions of the device layer 204 underlying thesecond portions 216 of the second surface 208 which are unmasked by themask layer 212 are successfully removed while the first portions 214 ofthe second surface 208 of the device layer 204 are protected by the masklayer 212. As shown in FIG. 2D, after the operation of removing theportions of the device layer 204 is completed, the cavities 220 areformed in the device layer 204, and the grid structure 218 including thecavities 220 is formed on the second surface 208 of the device layer204. For example, each of the cavities 220 may be formed to have across-section in a shape of rectangle. In addition, the cavities 220 areformed to be periodically arranged. A pitch between the cavities 220, adepth, a length and a width of each cavity 220 are modified according toproduct requirements.

As shown in FIG. 2E, in some examples, after the operation of formingthe grid structure 218 is completed, the mask layer 212 is removed fromthe first portions 214 of the second surface 208 of the device layer 204to expose the first portions 214 of the second surface 208, so as tocomplete the formation of the grid structure 218. In certain examples,the mask layer 212 is remained on the first portions 214 of the secondsurface 208 of the device layer 204 after the operation of forming thegrid structure 218 is completed.

Referring to FIG. 2F, in some examples, after the grid structure 218 isformed on the second surface 208 of the device layer 204, a lining layer222 may be optionally formed to cover the grid structure 218. Forexample, the lining layer 222 is conformal to the grid structure 218. Insome exemplary examples, the operation of forming the lining layer 222is performed using a thermal oxidation technique, in which the surfaceof the grid structure 218 of the device layer 204 is thermally oxidizedto form the lining layer 222 covering the grid structure 218. Thus, theoperation of forming the lining layer 222 is performed to form thelining layer 222 from silicon oxide while the device layer 204 is formedfrom silicon.

As shown in FIG. 2G, various color filters 224 a, 224 b, 224 c and 224 dare respectively formed in the cavities 220 of the grid structure 218.The color filters 224 a, 224 b, 224 c and 224 d are formed tocorrespondingly fill the cavities 220. In some examples, as shown inFIG. 2G, four kinds of color filters, i.e. the color filters 224 a, 224b, 224 c and 224 d, are formed. The operation of forming the colorfilters 224 a, 224 b, 224 c and 224 d includes arranging the colorfilters 224 a, 224 b, 224 c and 224 d in sequence and repeatedly. Insome exemplary examples, the operation of forming the color filters 224a, 224 b, 224 c and 224 d is performed to form red color filters, bluecolor filters, green color filters and white color filters. The whitecolor filters may be formed from a white color filter material orsilicon oxide. In various examples, only three kinds of color filters,such as red color filters, green color filters and blue color filters,may be formed in the cavities 220. In certain examples, four kinds ofcolor filters, such as red color filters, green color filters, bluecolor filters and yellow color filters, may be formed in the cavities220.

As shown in FIG. 2H, a passivation layer 226 is formed on the secondsurface 208 of the device layer 204, and covering the grid structure 218and the color filters 224 a, 224 b, 224 c and 224 d to substantiallycomplete a semiconductor layer 228. The passivation layer 226 is formedfor protecting the grid structure 218, and the color filters 224 a, 224b, 224 c and 224 d, and the device layer 204 from being damaged. In theexamples without any lining layer covering the grid structure 218, thepassivation layer 226 is formed to cover the second surface 208 of thedevice layer 204, the grid structure 218, and the color filters 224 a,224 b, 224 c and 224 d. In the examples that the lining layer 222 coversthe grid structure 218, the passivation layer 226 is formed to cover thelining layer 222 and the color filters 224 a, 224 b, 224 c and 224 d, inwhich the lining layer 222 is disposed between the color filters 224 a,224 b, 224 c and 224 d and the device layer 204 and between thepassivation layer 226 and the second surface 208 of the device layer204. The operation of forming the passivation layer 226 may includeforming the passivation layer 226 from silicon oxide, silicon nitride orsilicon oxynitride. In some exemplary examples, the operation of formingthe passivation layer 226 is performed using a plasma enhanced chemicalvapor deposition (PECVD) technique.

With the grid structure 218 formed on the second surface 208 of thedevice layer 204 using a portion of the device layer 204, there is nodistance between the grid structure 218 and the device layer 204, andphotoelectrons are generated in the grid structure 218, such that acrosstalk effect can be significantly improved, thereby increasingbrightness of light. Furthermore, no additional film is needed forforming the grid structure 218, so that the process cost is reduced.Moreover, the color filters 224 a, 224 b, 224 c and 224 d are disposedin the cavities 220 of the grid structure 218, so that thicknesses ofthe color filters 224 a, 224 b, 224 c and 224 d are substantially thesame, thereby enabling light transmission through the color filters 224a, 224 b, 224 c and 224 d to be uniform.

Referring to FIG. 3 with FIG. 2A through FIG. 2H, FIG. 3 is a flow chartof a method for manufacturing a semiconductor device in accordance withvarious embodiments. The method begins at operation 300, where asubstrate 200 is provided. At operation 302, a device layer 204 isformed on a surface 202 of the substrate 200, as shown in FIG. 2A. Theoperation of forming the device layer 204 is performed to form thedevice layer 204 on the surface 202 of the substrate 200 using, forexample, a deposition technique, an epitaxial technique or a bondingtechnique. The device layer 204 has a first surface 206 and a secondsurface 208 opposite to the first surface 206.

At operation 304, as shown 2E, a grid structure 218 is formed on thesecond surface 208 of the device layer 204 using, for example, apatterning technique. The operation of forming the grid structure 218includes forming the grid structure 218 including various cavities 220in the device layer 204. In some examples, in the operation of formingthe grid structure 218, a mask material layer 210 is firstly formed toblanketly cover the second surface 208 of the device layer 204, i.e. themask material layer 210 is formed to cover first portions 214 and secondportions 216 of the second surface 208 of the device layer 204, as shownin FIG. 2B. The operation of forming the mask material layer 210 may beperformed using a thermal oxidation process, in which the second surface208 of the device layer 204 is thermally oxidized to form the maskmaterial layer 210. For example, the device layer 204 is formed fromsilicon, and the mask material layer 210 is formed from silicon oxide.After the mask material layer 210 is formed, portions of the maskmaterial layer 210 on the second portions 216 of the second surface 208of the device layer 204 are removed, so as to form a mask layer 212which is disposed on the first portions 214 of the second surface 208and exposes the second portions 216 of the second surface 208, as shownin FIG. 2C. For example, the operation of removing the portions of themask material layer 210 may be performed using a photolithographytechnique and an etching technique. Then, as shown in FIG. 2D, portionsof the device layer 204 are removed from the second portions 216 of thesecond surface 208 of the device layer 204 to form the grid structure218 including the cavities 220.

In some examples, the operation of removing the portions of the devicelayer 204 from the second portions 216 of the second surface 208 of thedevice layer 204 is performed using an etching technique with the masklayer 212 as an etching mask. For example, the operation of removing theportions of the device layer 204 is performed using an anisotropic etchtechnique. In some exemplary examples, the operation of removing theportions of the device layer 204 is performed using TMAH as an etchantwhile the mask layer 212 is formed from silicon oxide and the devicelayer 204 is formed from silicon. The TMAH has high etching selectivitybetween the silicon oxide and silicon, so that the portions of thedevice layer 204 underlying the second portions 216 of the secondsurface 208 which are unmasked by the mask layer 212 are successfullyremoved while the first portions 214 of the second surface 208 of thedevice layer 204 are protected by the mask layer 212.

As shown in FIG. 2E, in some examples, after the operation of formingthe grid structure 218 is completed, the mask layer 212 is removed fromthe first portions 214 of the second surface 208 of the device layer 204to expose the first portions 214 of the second surface 208. In certainexamples, the mask layer 212 is remained on the first portions 214 ofthe second surface 208 of the device layer 204 after the operation offorming the grid structure 218 is completed.

In some examples, as shown in FIG. 2F, a lining layer 222 may beoptionally formed to cover the grid structure 218. For example, thelining layer 222 is conformal to the grid structure 218. In someexemplary examples, the operation of forming the lining layer 222 isperformed using a thermal oxidation technique, in which the surface ofthe grid structure 218 of the device layer 204 is thermally oxidized toform the lining layer 222 covering the grid structure 218. While thedevice layer 204 is formed from silicon, the operation of forming thelining layer 222 includes forming the lining layer 222 from siliconoxide.

At operation 306, as shown in FIG. 2G, various color filters 224 a, 224b, 224 c and 224 d are respectively formed in the cavities 220 of thegrid structure 218. The color filters 224 a, 224 b, 224 c and 224 d areformed to correspondingly fill the cavities 220. The color filters 224a, 224 b, 224 c and 224 d are arranged in sequence and repeatedly. Insome examples, as shown in FIG. 2G, four kinds of the color filters 224a, 224 b, 224 c and 224 d are formed, in which the color filters 224 a,224 b, 224 c and 224 d may include red color filters, blue colorfilters, green color filters and white color filters. The white colorfilters may be formed from a white color filter material or siliconoxide. In certain examples, four kinds of color filters, such as redcolor filters, green color filters, blue color filters and yellow colorfilters, may be formed in the cavities 220. In various examples, onlythree kinds of color filters, such as red color filters, green colorfilters and blue color filters, may be formed in the cavities 220.

At operation 308, as shown in FIG. 2H, a passivation layer 226 is formedon the second surface 208 of the device layer 204, and covering the gridstructure 218 and the color filters 224 a, 224 b, 224 c and 224 d tosubstantially complete a semiconductor layer 228. In the exampleswithout any lining layer covering the grid structure 218, thepassivation layer 226 is formed to cover the second surface 208 of thedevice layer 204, the grid structure 218, and the color filters 224 a,224 b, 224 c and 224 d. In the examples that the lining layer 222 isform to cover the grid structure 218, the passivation layer 226 isformed to cover the lining layer 222 and the color filters 224 a, 224 b,224 c and 224 d. The passivation layer 226 may be formed from siliconoxide, silicon nitride or silicon oxynitride. In some exemplaryexamples, the operation of forming the passivation layer 226 isperformed using a PECVD technique.

Referring to FIG. 4 with FIG. 2A through FIG. 2H, FIG. 4 is a flow chartof a method for manufacturing a semiconductor device in accordance withvarious embodiments. The method begins at operation 400, where asubstrate 200 is provided. At operation 402, as shown in FIG. 2A, adevice layer 204 is formed on a surface 202 of the substrate 200. Thedevice layer 204 is formed on the surface 202 of the substrate 200using, for example, a deposition technique, an epitaxial technique or abonding technique. The device layer 204 has a first surface 206 and asecond surface 208 opposite to the first surface 206.

At operation 404, as shown in FIG. 2C, a mask layer 212 is formed onfirst portions 214 of the second surface 208 of the device layer 204 andexposing second portions 216 of the second surface 208. In someexamples, in the operation of forming the mask layer 212, a maskmaterial layer 210 is firstly formed to blanketly cover the secondsurface 208 of the device layer 204, as shown in FIG. 2B. The operationof forming the mask material layer 210 may be performed using a thermaloxidation process. In some exemplary examples, the device layer 204 isformed from silicon, and the mask material layer 210 is formed fromsilicon oxide. Then, portions of the mask material layer 210 on thesecond portions 216 of the second surface 208 of the device layer 204are removed, so as to complete the mask layer 212. The operation ofremoving the portions of the mask material layer 210 may be performedusing a photolithography technique and an etching technique.

At operation 406, as shown in FIG. 2D, portions of the device layer 204are removed from the second portions 216 of the second surface 208 ofthe device layer 204 to form the grid structure 218 including thecavities 220, in which the cavities 220 are formed in the device layer204. In some examples, the operation of removing the portions of thedevice layer 204 from the second portions 216 of the second surface 208of the device layer 204 is performed using an etching technique with themask layer 212 as an etching mask. For example, the operation ofremoving the portions of the device layer 204 is performed using ananisotropic etch technique. In some exemplary examples, the operation ofremoving the portions of the device layer 204 is performed using TMAH asan etchant while the mask layer 212 is formed from silicon oxide and thedevice layer 204 is formed from silicon.

As shown in FIG. 2E, in some examples, after the grid structure 218 isformed, the mask layer 212 is removed from the first portions 214 of thesecond surface 208 of the device layer 204 to expose the first portions214 of the second surface 208. In certain examples, the mask layer 212is remained on the first portions 214 of the second surface 208 of thedevice layer 204 after the operation of forming the grid structure 218is completed.

At operation 408, as shown in FIG. 2F, a lining layer 222 is formed tocover the grid structure 218. For example, the lining layer 222 isconformal to the grid structure 218. In some exemplary examples, theoperation of forming the lining layer 222 is performed using a thermaloxidation technique. Thus, while the device layer 204 is formed fromsilicon, the operation of forming the lining layer 222 includes formingthe lining layer 222 from silicon oxide.

At operation 410, as shown in FIG. 2G, various color filters 224 a, 224b, 224 c and 224 d are respectively formed in the cavities 220 of thegrid structure 218 on the lining layer 222. The color filters 224 a, 224b, 224 c and 224 d are formed to correspondingly fill the cavities 220.The color filters 224 a, 224 b, 224 c and 224 d are arranged in sequenceand repeatedly. In some examples, four kinds of the color filters 224 a,224 b, 224 c and 224 d are formed, in which the color filters 224 a, 224b, 224 c and 224 d may include red color filters, blue color filters,green color filters and white color filters. In certain examples, fourkinds of color filters, such as red color filters, green color filters,blue color filters and yellow color filters, may be formed in thecavities 220. In various examples, only three kinds of color filters,such as red color filters, green color filters and blue color filters,may be formed in the cavities 220.

At operation 412, as shown in FIG. 2H, a passivation layer 226 is formedto cover the lining layer 222 and the color filters 224 a, 224 b, 224 cand 224 d to substantially complete a semiconductor layer 228. Thepassivation layer 226 may be formed from silicon oxide, silicon nitrideor silicon oxynitride. In some exemplary examples, the operation offorming the passivation layer 226 is performed using a PECVD technique.

In accordance with an embodiment, the present disclosure discloses asemiconductor device. The semiconductor device includes a substrate, adevice layer, color filters and a passivation layer. The device layeroverlies the substrate, and has a first surface and a second surfaceopposite to the first surface. The device layer includes a gridstructure on the second surface, and the grid structure includes variouscavities. The first surface is adjacent to the substrate. The colorfilters fill the cavities. The passivation layer is disposed on thesecond surface of the device layer, and covers the grid structure andthe color filters.

In accordance with another embodiment, the present disclosure disclosesa method for manufacturing a semiconductor device. In this method, asubstrate is provided. A device layer is formed on the substrate, inwhich the device layer has a first surface and a second surface oppositeto the first surface, and the first surface is adjacent to thesubstrate. A grid structure is formed on the second surface of thedevice layer, in which the grid structure is formed to include variouscavities. Color filters are formed in the cavities. A passivation layeris formed on the second surface of the device layer and covering thegrid structure and the color filters.

In accordance with yet another embodiment, the present disclosurediscloses a method for manufacturing a semiconductor device. In thismethod, a substrate is provided. A device layer is formed on thesubstrate, in which the device layer has a first surface and a secondsurface opposite to the first surface, and the first surface is adjacentto the substrate. A mask layer is formed to cover first portions of thesecond surface of the device layer and to expose second portions of thesecond surface. Portions of the device layer are removed from the secondportions of the second surface of the device layer to form a gridstructure on the second surface, in which the grid structure includesvarious cavities in the device layer. A lining layer is formed to coverthe grid structure on the second surface of the device layer. Colorfilters are formed in the cavities on the lining layer. A passivationlayer is formed to cover the lining layer and the color filters.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

1-5. (canceled)
 6. A method for manufacturing a semiconductor device,the method comprising: providing a substrate; forming a device layer onthe substrate, wherein the device layer has a first surface and a secondsurface opposite to the first surface, and the first surface is adjacentto the substrate; forming a grid structure in the second surface of thedevice layer, wherein the grid structure is formed to comprise aplurality of cavities; forming a plurality of color filters in thecavities; and forming a passivation layer on the second surface of thedevice layer and covering the grid structure and the color filters. 7.The method of claim 6, wherein forming the device layer comprisesforming the device layer from silicon.
 8. The method of claim 6, whereinforming the grid structure comprises: forming a mask layer to coverfirst portions of the second surface of the device layer and to exposesecond portions of the second surface; and removing portions of thedevice layer from the second portions of the second surface to form thecavities in the device layer.
 9. The method of claim 8, wherein formingthe mask layer comprises forming the mask layer from silicon oxide. 10.The method of claim 8, wherein forming the mask layer comprises: forminga mask material layer to blanketly cover the second surface of thedevice layer; and removing portions of the mask material layer on thesecond portions of the second surface of the device layer.
 11. Themethod of claim 10, wherein forming the mask material layer is performedusing a thermal oxidation technique.
 12. The method of claim 8, whereinremoving the portions of the device layer is performed using ananisotropic etch technique.
 13. The method of claim 8, wherein removingthe portions of the device layer is performed using tetramethyl amminiumhydroxide as an etchant.
 14. The method of claim 6, between forming thegrid structure and forming the color filters, the method furthercomprises forming a lining layer to cover the grid structure.
 15. Themethod of claim 14, wherein forming the lining layer comprises formingthe lining layer from silicon oxide.
 16. The method of claim 14, whereinforming the lining layer is performed using a thermal oxidationtechnique.
 17. The method of claim 14, wherein forming the passivationlayer is performed using a plasma enhanced chemical vapor depositiontechnique.
 18. A method for manufacturing a semiconductor device, themethod comprising: providing a substrate; forming a device layer on thesubstrate, wherein the device layer has a first surface and a secondsurface opposite to the first surface, and the first surface is adjacentto the substrate; forming a mask layer to cover first portions of thesecond surface of the device layer and to expose second portions of thesecond surface; removing portions of the device layer from the secondportions of the second surface of the device layer to form a gridstructure on the second surface, wherein the grid structure comprises aplurality of cavities in the device layer; forming a lining layer tocover the grid structure on the second surface of the device layer;forming a plurality of color filters in the cavities on the lininglayer; and forming a passivation layer to cover the lining layer and thecolor filters.
 19. The method of claim 18, wherein forming the devicelayer comprises forming the device layer from silicon; and forming themask layer comprises forming the mask layer from silicon oxide using athermal oxidation technique.
 20. The method of claim 19, wherein theoperation of removing the portions of the device layer is performedusing an etch technique with tetramethyl amminium hydroxide as anetchant.
 21. The method of claim 6, wherein the device layer is formedon the substrate by using a deposition technique, an epitaxialtechnique, or a bonding technique.
 22. The method of claim 6, whereinthe cavities are arranged periodically.
 23. The method of claim 6,wherein the color filters includes red color filters, blue colorfilters, green color filters, and white color filters.
 24. The method ofclaim 23, wherein the white color filters are formed from silicon oxide.25. The method of claim 6, wherein the passivation layer is formed fromsilicon oxide, silicon nitride, or silicon oxynitride.